Printing apparatus

ABSTRACT

Apparatus for printing characters from a multi-position printing head provide pulsed motive power subject to terminal fluctuation. This motive power is yieldably coupled to the printing head to pulse the printing head into a predetermined position. The printing head is releasably retained at such predetermined position, and motive power fluctuation is absorbed with the yieldable coupling.

United States Patent 1191 1111 3, McManaman 1 Oct. 28, 1975 PRINTING APPARATUS 3,307,676 3/1967 Hickerson 101/110 x 3,384,216 5/1968 Th [75] Raymnd McManaman 3,669,016 6/1972 K135: 101/93 (3 Glendora, Calif.

[ Assigneel & Howeucmnpany, Chicago Primary ExaminerClifford D. Crowder Assistant ExaminerEdward M. Coven [22] Filed; No 30 1973 Attorney, Agent, or Firm-Benoit Law Corporation [21] Appl. No.: 420,739 I [57] ABSTRACT US. Cl. Apparatus for printing characters from a multi- 101/9322 position printing head provide pulsed motive power (3L2 subject to terminal fluctuatio m nofive power is Field of Search 101/93 99, yieldably coupled to the printing head to pulse the printing head into a predetermined position. The

197/18, 53; 235/144 5 printing head is releasably retained at such predetermined position, and motive power fluctuation is ab- References. Cited sorbed with the yieldable coupling.

UNITED STATES PATENTS 3,018,953 l/l962 Deutsch 235/144 s 18 Clam, 17 D'awmg F'gures l 1 I I l US. Patent Oct. 28, 1975 Sheet 2 of6 3,915,086

U.S. Patent 'Oct.28, 1975 Sheet30f6 3,915,086

U..S. Patent Oct. 28, 1975 Sheet40f6 3,915,086

9 m in m Q S x US. Patent Oct. 28, 1975 Sheet 5 of6 3,915,086

PRINTING APPARATUS CROSS REFERENCES The following United States Patents and/or copending patent applications, filed of even date, disclose or disclose and claim subject matter which is shown herein and/or which may be employed in the practice of the subject invention. These patents or applications are assigned to the same assignee as the subject patent application or patent and are herewith incorporated by reference herein.

Ser. No. 420,503 entitled Communication Methods and Billing Systems, by R. A. Boyle, E. S. Gilchrist and R. L. Visser;

Ser. No. 420,734, entitled Communication Methods and Billing Systems, by E. S. Gilchrist and R. L. Visser;

Ser. No. 420,735, entitled Methods and Apparatus for Performing a Function Relative to a Card, by F. F. Grant;

Ser. No. 420,736, entitled Printing Apparatus, by E. S. Gilchrist and F. F. Grant;

Ser. No. 420,737, entitled Sheet Advancing Methods and Apparatus, by F. F. Grant;

Ser. No. 420,738, entitled Card Advancing and Function Performinng Methods and Apparatus, by D. W. Westover and F. F. Grant;

Ser. No. 420,740, entitled Character Expressing and Printing Methods and Apparatus, by E. S. Gilchrist and A. B. Nayak.

BACKGROUND OF THE INVENTION 1. Field of the Invention The subject invention relates to printing and, more specifically, to printing apparatus employing multiposition printing heads.

2. Description of the Prior Art In connection with printing equipment employing multi-position printing heads, the requirement frequently arises to stop the printing head instantly in any desired position without undue wear and tear of mechanical parts.

The problem becomes particularly acute when the printing head is to be stepped at intervals in the millisecond range. While stepping motors can be obtained which will step the printing head in such short time intervals, such motors have the drawback of providing motive power subject to terminal fluctuation.

The expression terminal fluctuation" is herein employed to designate the positional fluctuation, typically in the form of a number of back and forth movements or vibrations, that occur at the end of a given stepping cycle. By way of example, if a stepping motor through its output shaft provides eight motive power pulses to step a printing head through eight positions in, say, milliseconds or less, the motor output shaft will not instantly stand still at the end of the pulsing operation but will circularly vibrate the printing head in opposite senses for a finite period of time. This, of course, limits the attainable printing speed, since high quality printing cannot commence as long as the printing head is vibrating erratically.

Electrical schemes for stopping the motor instantly have not so far been able to solve the problem with sufficient accuracy and would at any rate b e too costly for many applications. I

Brute force solutions which arrest the motor instantly impose high wear and tear and accelerate equipment failure.

SUMMARY OF THE INVENTION It is an object of this invention to overcome the above mentioned disadvantages.

It is a more specific object of the invention to provide improved printing apparatus employing multi-position printing heads.

It is a related object of this invention to increase printing speed by materially reducing the stopping time of printing heads.

It is a further related object of the invention to enable the use of motive power providing equipment which is subject to terminal fluctuation for the operation of multi-position printing heads.

It is a further related object of the invention to reduce the start-up inertia load on driving motors for multi-position printing heads.

Other objects of the invention appear in the further course of this disclosure.

The subject invention resides in apparatus for printing characters from a multiposition printing head, and resides, more specifically, in the improvement comprising, in combination, means for providing pulsed motive power subject to terminal fluctuations, means advancing said printing head with said pulsed motive power to any printing position, said advancing means include means for yieldably coupling said motive power means to said printing head, means coupled to said printing head for releasably retaining said printing head in any printing position whereby said yieldable coupling means absorb said motive power terminal fluctuation, and means including printing hammer means separate from said releasable retaining means for printing characters from said printing head. From another aspect thereof, the invention resides in apparatus for printing characters, and resides more specifically in the improvement including in combination a rotary character printing head having a plurality of angular printing positions, means including a stepping motor having a motor shaft for providing about an axis of rotation pulsed rotary motive power for stepping said printing head, said pulsed rotary motive power being subject to terminal fluctuation, means for yieldably coupling said printing head to said stepping motor shaft, means including a spring-biased detent for releasably retaining said rotary printing head in each of said angular printing positions upon deenergization of said stepping motor means whereby said yieldable coupling means absorb said terminal fluctuation of said rotary motive power, and means including printing hammer means separate from said printing head retaining means for printing characters from said printing head.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will become more readily apparent from the following detailed description of preferred embodiments thereof, illustrated by way of example in the accompanying drawings, in which like reference numerals designate like or functionally equivalent parts, and in which:

FIG. 1 is a plan view ofa record card that may be employed in the practice of the subject invention;

FIG. 2 is a plan view, with removed top, of a compact card moving and function performing apparatus employing printing equipment in accordance with a preferred embodiment of the subject invention;

FIG. 3 is a section taken along the line 3 3 in FIG. 2, with the printing mechanism having been removed;

FIG. 4 is a section taken along the line 4 4 in FIG. 2, with the printing mechanism having been removed;

FIG. 5 is a section taken along the line 5 5 in FIG. 2, with the printing mechanism having been removed;

FIG. 6 is an offset section taken along the line 6 6 in FIG. 3;

FIG. 7 is a partial sectional elevational taken along the line 7 7 in FIG. 6;

FIG. 8 is an offset section taken along the line 8 8 in FIG. 4;

FIGS. 9 and 10 are enlarged fragmentary views of FIG. 4;

FIG. 11 is a fragmentary sectional view of a printing mechanism in accordance with a preferred embodiment of the subject invention taken at the line 11 11 in FIG. 2;

FIG. 12 is a partial section taken along the line 12 12 in FIG. 11;

FIG. 13 is a plan view of the printing head with associated parts;

FIG. 14 is a partial section taken along the line 14 14 in FIG. 11;

FIG. 15 is a sectional elevation of a detail of FIG. 11

on an enlarged scale;

FIG. 16 is a modified illustration, in an enlarged scale, of a detail of the printing apparatus shown in FIGS. 11 to 15; and

FIG. 17 is a block diagram of electronic equipment used in portable billing apparatus herein disclosed and controlling functions thereof.

DESCRIPTION OF PREFERRED EMBODIMENTS By way of example, and not by way of limitation, the apparatus 28 shown in the drawings may have utility as a portable billing apparatus and will occasionally be referred to as such in the further course of this disclosure. For instance, the portabele billing apparatus 28 may be employed to provide bills and billing information at customers addresses for utility consumption or services rendered.

In the latter vein, FIG. 1 shows a record card 23 on which account and billing information has been printed in three fields 31, 32 and 38. Depending on the application, some of that information may be preprinted on the record card 23, and the remaining information may then be printed on the card 23 by the portable billing apparatus 28. The record parts 31 and 38 may then be handed to the particular customer as a statement or bill. The record part 32 may be returned to the billing center for the purpose of subsequent verification of the amount due from the particular customer. When paying his bill, the customer would send the record part 38 along with his payment and the record part 38 would then be compared with the record part 32 to verify that the customer has paid his entire bill.

The portable billing apparatus 28 in accordance with the illustrated preferred embodiment of the subject invention will now be described with the aid of FIGS. 2

The portable billing apparatus 28 has a housing 41 having a slot 42 at one end thereof for receiving a record card 23 on which data are to be printed. The record card 23, shown in dotted outline in FIG. 2, may be of the type shown in FIG. 1 and described above.

A supporting structure with side frames 43 and 44 is provided inside the housing 41 for mounting the mechanical parts of the billing apparatus 28. A card receiving chamber 45 is defined inside the slot 42 by a pair of card guides 46 and 47 having flared or inclined receiving lips (see FIGS. 2 and 4).

Lateral guides 51 and 52 have flared or inclined lips 53 and 54 for guiding the card 23 laterally where necessary.

A card receiving platform 56 is resiliently mounted below the receiving chamber 45 by springs 47' relative to a supporting plate 48. If desired, several cards 23 may be inserted at a time through the slot 42 and receiving chamber 45 and stored on the platform 56. A lip 49 on the supporting plate 48 prevents more than one card from being fed at a time from the platform 56 to the printing area of the portable biller.

The portable biller 28 includes a handle 61 which has a manually engageable piece 62. The handle 61 is attached by screws 63 to an actuator block 64 which is slidable along bars 65 and 66.

A screw 68 connects a lug 69 to an extension bar of an actuating arm 72. The actuating arm 72 has an offset extension 73 which engages the forward end of a carriage 74 (see FIG. 4).

In this manner, the handle 61 is capable of causing sliding motion of the carriage 74 along a track 76. The carriage 74 has an extension lip 77 bent over the actuating arm extension 73.

A resilient bracket 79 mounts a roller 81 on the carriage 74 for limited rotary movement relative to the platform 56 or the card or cards located thereon.

A limited peripheral portion of the roller 81 is occupied by a high friction material 82, while the remaining peripheral portions of the roller 81 are occupied by a low friction material 83. For the purpose of illustration, the low friction material 83 has been shown in black in FIG. 4, while the high friction material 82 has been shown in white.

The roller 81 has a flat top 84 adjacent the bracket 79 so that the roller 81 only capable of limited rotary movement, such as an angular movement of 15 in both clockwise and counterclockwise directions.

The roller 81 is a unidirectional card advancing device. If the handle 61 and the carriage 74 are pushed to the left as seen in FIGS. 3 and 4, the high friction between the roller portion 82 and the inserted card 23 above the platform 56 causes the roller 81 to rotate slightly. This rotation is limited by the abutment of the flat roller top 84 with the supporting bracket 79 so that the high friction roller portion 82 remains in contact with the inserted cart 23.

Accordingly, upon further movement of the carriage 74, the card engaged by the high friction portion 82 of the roller 81 is driven to the left into the path 85 shown in FIG. 4. A support 86 and a hold down spring 87 are mounted adjacent the gate 85. The support 86 functions as a guide.

As seen in FIG. 9, the guide 86 and hold down spring 87 cooperate in positioning the leading edge of the advancing card 23 in a recess 88 of a drum 89. The object at this juncture is to wrap the card around the drum for printing and other purposes more fully described below.

To this end, the drum 89 has a shaft 91 which, as more fully seen in FIG. 8, is rotatable in two bearings 93 and 94 attached to the frame structure 43 and 44. A gear wheel 95 is attached to the drum 98 in order to drive the drum.

As seen in FIG. 3, a hook 97 is attached to the drive block 64. When the handle 61 advances the drive block 64 to the left, the hook 97 engages a hook 98 fastened to a drive belt 99. The drive belt 99 is in forcetransmitting engagement with the drive gear wheel 95 of the drum 98 and extends also over an idler pulley 100 seen in FIg. 3.

Accordingly, the advancing block 64 drives the drum 98 via the hooks 97 and 98 and the belt 99. The drum 98 is thus rotated counterclockwise in the direction of an arrow 101 shown in FIGS. 4 and 9. The advanced card 23 is wrapped around at least part of the periphery of the drum 98 during such rotary motion. To this end, belts 103 of a flexible metal or a flexible, tough plastic are attached by fasteners 104 to the periphery of the drum 89. These belts 103 further extend from the drum 89 to and around the periphery of a drum 105. The ends of the belts 103 which are opposite to the ends attached to the drum 89 are attached to the drum 105.

The drum 105 has a shaft 106 rotatable in bearings 108 and 109 attached to the frame structures 191 and 192. When the drum is rotated counterclockwise in the direction of the arrow 101 by the drive belt 99, portions of the belt 103 are progressively unwound from the drum 105 and wound onto the advancing card 23 on the drum 89.

In this manner, the card 23 is progressively wound onto the drum 89 and is held down on the drum by the belts 103.

Wrapping of the card 23 around at least part of the drum 89 is not resisted by the card drive roller 81. Rather, the advancing drum 98 and belts 103 will pull the engaged card 23 along the platform 56 which imparts a clockwise rotary motion to the rollers 81. In this manner, the low friction portion 83 of the roller will be drawn into contact with the sliding card. Because of the low friction nature of the roller portion 83, the roller 81 will then not resist advancement of the card along the platform 56 and onto the drum 89.

While the handle 61 and drive belt 99 are being advanced, a coil or clock spring 110 is partially unwound from the drum 1 12 shown in FIGS. 3 and 6. A shaft 1 14 is attached to the mounting structure 44 in order to mount the spring drum 112 for rotary movement.

A coil or clock spring 115 is wound when the wrapped portions of the belts 103 are unwound from the drum 105 by the rotating main drum 89. The spring 115 has an end 116 attached to the shaft of the drum 105. An opposite end of the spring 115 extends around a pin 117 which is attached to the mounting structure 191. In this manner, the belts 103 are spring tensioned when they are wound onto the card on the drum 89.

By way of alternative, the shaft 106 can be made stationary relative to the mounting structures 191 and 192. In that case, the inner end of the spring 115 could be attached to the shaft 106 and the outer end of the spring 115 could be attached to the drum 105, with the drum 105 being mounted for rotation on the shaft 106.

At this juncture, a closer consideration of the nature and function of the slide block assembly 64 will be helpful. As seen in FIG. 3, the slide block assembly 64 is composed to a first slide block 122 and a second slide block 123. The handle 61 is attached by the fasteners 63 to the slide block 122. The lower block has a fork portion 124 which straddles a bushing 125 slidable on the bar 65. Similarly, the block 122 has a fork 127 which straddles a bushing 128 slidable on the bar 66.

The bushing 125 fits into a bore in the slide block 122, while the bushing 128 fits into a bore in the slide block 123. In this manner, the handle 61 moves the blocks 122 and 123 of the slide block assembly 64 in unison until the block 123 is stopped.

This occurs when a roller 1311 drops into a depression 132 in a bar 133 as shown in FIG. 7. The roller 131 is mounted by a linkage 135 for rotation relative to the bar 133.

The linkage 135 is connected to a bracket 136 which is attached to the bar 71. The bar 71, in turn, is attached to the slide block 123 at 68 and 69.

When the slide block assembly 64 is advanced by the handle 61, the roller 31 rolls along the bar 133 until it drops into the depression 132 as indicated in FIG. 7. A spring 137 biases the roller 131 against the bar 133 and into the depression 132. I

Engagement of the roller 131 with the bar 133 at the depression 132 stops further movement of the slide block 123. Continued movement of the handle 61 then pulls the bushing 123 by action of the fork 127 away from the slide block 123. At the same time, the slide block 122 pulls off the bushing 125 retained by the fork 124 of the arrested slide block 123. At that instant, the carriage 74 will have stopped its motion on the track 76 since it is connected at 73 and 77 to the bar 71 which, in turn, is attached to the slide block 123 as mentioned above. This means that the uunidirectional card advancing roller 81 will have advanced the leading edge of the engaged card 23 into the recess 88 and under part of the belt 103 as shown in FIG. 9, when the sliding block 122 separates from the sliding block 123.

Continued movement of the [handle 61 will then further advance the sliding block 122 toward a stop 138.

At this juncture, it will be noted that the hook 97 shown in FIG. 3 is attached to an extension 139 of the sliding block 122 and is initially spaced from the hook 98 on the drive belt 99.

This provides a lost motion connection between the hooks 97 and 98, whereby the hook 98 only becomes engaged when the leading edge of the advanced card 23 has been located in the recess 88 of the main drum 89 as shown in FIG. 9. Once the engagement between the hooks 98 and 99 has been established, further movement of the slide block 122 away from the then arrested slide block 123 will advance the drive belt 99 which, in turn, will rotate the drum 98 counterclockwise in the direction of the arrow 101 by action on the drive wheel 95. In this manner, the advanced card 23 will be wrapped around at least part of the periphery of the main drum 89 as mentioned above.

A dashpot assembly 141 controls the forward speed of the slide block assembly 64. The dashpot assembly 141 has an air cylinder 142 attached to the mounting structure 44 by a bracket 143. A piston 145 shown in dotted lines in FIG. 3 is fitted for sliding movement in the air cylinder 141. An adjustable air valve 146 on the cylinder 141 permits adjustment of the rate of movement of the piston in the cylinder.

A piston rod 147 is connected to the piston 145. A link 148 connects the free end of the piston rod 147 to a lever 149 which is pivoted relative to the mounting structure 44 and 151.

A link 152 is pivoted on the extension 139 of the slide block 122 and acts on the lever 149 to move the piston 145 in the cylinder 142 to the left as seen in FIG. 3, against the air resistance provided by the valve 146 and against the bias of a spring 153.

This occurs when the slide blocks 122 and 123 are advanced by the handle 61 and continues when the slide block 122 is further advanced by the handle 61 after separation from the slide block 123; if desired.

At the end of the track provided by the bars 65 and 66, motion of the slide block 122 is arrested by a stop 138. The slide block 122 may then be returned to the slide block 123 as more fully described below.

A double pawl 155 acts on a'ratchet wheel 156 to arrest rotary movement of the drum 89 under the influence of the tensioned spring 115 and rotary movement of the drum 105 also under the influence of the tensioned spring 115. As shown in FIG. 8 the ratchet wheel 156 is connected to the drum 89.

The pawl 155 may now be actuated in a controlled manner to permit stepped movements of the drum 89 during printing of the desired information on the wrapped card on the drum. This phase of the operation of the portable printer 28 will be more fully described below.

For the purpose of the present disclosure, it is assumed that the required information has been printed onto the wrapped card and that it is desired to return this card 23 to the exit slot 42.

At this juncture, it will be noted that the link 152 is designed as a trigger biased by a spring 157. Accordingly, a link 152, which will override the free end of the lever 149 during movement of the slide block 122 toward the stop 138, can move back over the free end of the lever 149 when the slide block 122 is returned to its original position (see FIG. 3).

In the meantime, the bias spring 153 is free to return the 'lever 149 to its original position shown in FIG. 3.

During the printing process, the spring 115 rotates the drum 89 clockwise in the direction of an arrow 161 as seen in FIG. 10. Such movement of the drum 89 will eventually cause an upwrapping of the card 23 from the drum 89. During such unwrapping the hold down spring 87 will cause the then leading edge of the card 23 to impinge upon the guide 86 at its lower surface as shown in FIG. 10. This guides the card 23 into a return gate or channel 162.

During such unwrapping of the card, the spring 115 rotates the drum 105 counterclockwise as seen in FIG. 4 in order to wind the previously unwound portions of the belts 103 again onto the drum 105. In this manner,

the drum 89 and the bias of the partially unwound spring 110 may then be employed to return the slide block 122 to its midposition. In that case the gear wheel 95 acts through the pin 293' and arm 292 to advance the drum 89 in the forward direction when a card is being wound thereon. The drum 89 then stays in the advanced position until the double pawl 155 is released. While the drum stays in the advanced position, the spring 110 returns the gear wheel 95, drive belt 99 and slide block 122 to a midposition.

It will be recalled at this juncture that the slide block 122 became separated from the slide block 123 when the roller 131 became arrested in the recess 132 of the bar 133, as shown in dotted lines in FIG. 7.

The partial backward movement of the handle 61 just described may be effected in one operation with the previously described forward actuation. In that case the operator would actuate the handle 61 to push the slide block 122 forward to the maximum advanced position 138 and would then actuate the handle '61 to return the slide block 122 into engagement with the slide block 123.

In accordance with the illustrated preferred embodiment of the invention, the slide block 123 is connected the spring 115 also causes rotation of the drum 89 in 55 the direction of the arrow 161. For this to occur it is necessary that he hook 97 on the slide block 122 be spaced from the hook 98 on the drive belt 99 sufficiently to permit an unwrapping of the card 23 from the drum 89.

By way of example, this may be accomplished by manually engaging the handle portion 62 and retracting the handle 61 from the end position at 138 to the midposition at which the slide block 122 again engages the previously separated slide block 123. Alternatively, and in accordance with the illustrated preferred embodiment, an arm 292 cooperates with a pin 293' to form a one-way clutch between the gear wheel 95 and to a free end of a spring 164 shown in FIG. 7 via the bar 71, bracket 136 and fastener 165. The spring 164 is wound on a drum 166 which is rotatable about a shaft 167 as shown in FIG. 7. The spring 164 is tensioned to wind itself fully onto the drum 166.

as seen in FIG. 3. Similarly, the operator will feel the instant at which the slide block 122 has reengaged the side block 123 since the spring 164 is then wound on the drum 166 except for a small end portion attached to the bracket 136, and since the roller 131 is then arrested in the recess 132 of the bar 133.

The operator will then release the handle portion 62 until the printing process has been completed and the card has been unwrapped from the drum 89.

The leading edge of the unwrapping card proceeds through the gate 162 into a return chamber 167 delimited by shield 168, and onto a platform 169.

At this juncture, a function which takes place during the previously described advancement of the slide block 164 has to be considered. In particular, a roller 171 is advanced from its initial position shown in FIG. 4 to an advanced position near the card return chamber 167 when the slide block 64 is first advanced to the left as seen in FIG. 3. To this end, an arm 172 shown in FIGS. 3 and 4 projects from the bar 71 which, as previously mentioned, has a portion 69 attached to the lower slide 123 at 68.

The actuating arm 172 has a pin 172 which engages a carriage 173 as shown in FIG. 4. Accordingly, the

carriage 173 is advanced along a track 174 in a direction toward the card return chamber 167 when the slide block 64 is first moved to the left by the handle 61 from its initial position shown in FIG. 3. The carriages 74 and 173 thereby move in unison since they are both actuated from the same bar 71 attached to the slide block 123. e j N Both carriages 74 and 173 stop when the roller 131 becomes arrested in the recess 132 of the bar 133 shown in FIG. 7 and when the slide 122 then separates from the slide 123 as previously described.

At that juncture, the roller 171 is located in the vicinity of the card return chamber 167. Like the roller 81, the roller 171 is designed as a unidirectional card advancing device having a portion 176 of high friction material extending over part of its periphery and a portion 177 of low friction material extending over the remainder of its periphery. The roller 171 is mounted for limited rotary movement on a resilient support 178 which is attached to the carriage 173. A flat roller top 179 limits angular movement of the roller 171 to about in each direction.

Because of the presence of the low friction portion 177 of the roller 171, the leading edge of the returning card can readily slide in between the platform 169 and the roller 171 since the rotational position of the roller 171 is then such that the high friction portion 176 of the roller is spaced from the return platform 169. Also, the shield or plate 168 is resiliently mounted by springs 181 while the roller 171 is resiliently mounted by the previously mentioned support 178.

After the printing process as to the particular card 23 has been completed, the operator engages the handle 61 at its portion 62 and moves the slide block assembly 64 to the right as seen in FIG. 3. This actuates the carriages 74 and 73 from their above mentioned advanced position toward their initial position shown in FIG. 4. In terms of roller 81, this movement has no effect on any card, since it will cause position of the low friction portion 83 adjacent the platform 56.

Accordingly, no card is removed from the platform 56, even if more than one card were previously posi tioned on the platform 56.

On the other hand, movement of the carriage 173 from the above mentioned advanced position toward the initial position shown in FIG. 4 will rotate the roller 171 sufficiently to place the high friction portion into engagement with the card that has been returned through the chamber 167. Accordingly, the returning roller 171 will grip the card with its high friction portion and will slide it along the return platform 169 thereby separating it fully from the drum 89.

In this manner, the unidirectional card advancing device in the form of the roller 171 will place the leading edge of the returned card at the slot 42, such that the returned card 23 can be manually engaged and removed from the apparatus 28. In the process of its renewal, the card will subject the roller 171 to a limited angular movement such that the low friction portion 177 moves into engagement with the card. The roller 171 will then offer no resistance to a manual removal of the card from the printing apparatus 28. The next card may then be moved into engagement with the drum 89 in the above mentioned manner by actuation of the handle 61.

The printing process will now be fully described with reference to the accompanying drawings.

In particular, FIG. 5 shows the previously mentioned double pawl 155 which pivots around an axis 183. The pawl 155 is of a ferromagnetic material and is actuated by electromagnetic coils or solenoids 184 and 185 located on an armature 186. The pivot shaft 183 may be connected to the armature 186.

The double pawl 155 is designed in the manner of an escapement which, upon alternative energization of the coils 184 and 185, will permit stepped advancement of the ratchet wheel 156 and drum 89 in the direction of the arrow 187 which corresponds to the arrow 161 in FIG. 10. In this manner, advancement of the drum 89 can be easily controlled so that the wrapped card 23 on the drum is located, row for row, in the desired positions for the printing process.

As shown in FIGS. 2 and 4, the previously described roller and the printing assembly 189 are supported by side plates 191 and 192 which are pivoted relative to the frame structure at 193 so that the roller 105 and the printing assembly 189 can be swung outwardly as shown in phantom outline at 194 in FIG. 4. This facilitates servicing of the apparatus and access to the card on or at the drum 89.

As shown in dotted lines at 195 in FIG. 11, the printing mechanism 196 is detachable as a unit from the assembly 189. The printing mechanism is supported by a frame structure 198 having plates 199 and 200 cross tied together by rods 201, 202, 203 and 204.

The printing mechanism 196 has a mounting frame 206 pivotally mounted on rod 202. A bias spring 207 urges the frame 206 to its open position. A screw 208 retains the frame 206 in its active position shown in FIG. 11 against the bias of the spring 207.

A motor 209 is mounted on the frame 206. The motor 209, when energized, drives a shaft 212 which has a flexible coupling 213 attached thereto in a stepped manner.

The flexible coupling 213 links the motor shaft 212 to a printing head 214 shown in FIGS. 11 to 13. The flexible coupling 213 isolates the printing head 214 from pulsating motions which the motor shaft 212 executes at the end of a stepping operation. To this end, the flexible coupling 213 has buffer springs 216 which resiliently interconnect the coupling members 217 and 218. A set screw 219 attaches the coupling member 217 to the motor shaft 212.

The coupling part 218 forms a collar which conically blends into a ring 221 which has a plurality of notches 222, the number of which corresponds to the number of desired angular positions of the printing head. At least one detent 224 is biased by a spring 225 into the notches 222. In this manner, the motor 209 is capable of stepping the printing head to any desired angular position. However, pulsating motions of the motor shaft 212 are not transmitted to the printing head.

Rather, the detent 224 cooperating with notches 222 will retain the printing head stationary in any stepped position, while the coupling 2113 with its buffer springs 216 will absorb motor shaft pulsations.

The printing head 214 has a plurality of flexible arms 226 projecting radially from a base 227. The base 227 is attached to the notched ring; 221 and thus to the coupling piece or collar 218.

Each flexible arm 226 of the printing head has a flat tab at its extremity. The tabs 228 may be rectangular as shown in FIG. 13.

The tabs 228 of the printing head carry raised alphanumeric or clear text characters 229 or raised code text or encoded characters 231 in such an arrangement that an encoded character is located at a position 232 whenever its corresponding alphanumeric character is located at a position 233. In this manner, it is possible to print clear text and its corresponding encoded text simultaneously on a card 23" at different locations thereof. In particular, the printer according to the illustrated preferred embodiment is capable of printing information in clear text in either of the record parts 31 and 38 and simultaneously in code text in the record part 32 shown in FIG. 1.

To this end, the printer has two hammers 234 and 235 which are simultaneously struck by two actuators 236 and 237 which are simultaneously actuated by a common magnetic armature 238.

As shown in FIG. 14, the armature 238 is pivoted relative to a bracket 239 by pins 241.

Each of the hammers is biased to a retracted position by a spring 243 located in a relatively stationary housing 244.

In order to print corresponding alphanumeric and encoded characters, and electromagnetic coil or solenoid 246 is energized to attract the armature 238. This causes the actuators 236 and 237 to actuate the hammers 234 and 235 simultaneously, whereby these hammers simultaneously strike the tabs 228 which contain raised forms of the particular alphanumeric character and its encoded counterpart.

Ink for the printing process is derived from a ribbon 248 which is interposed between the printing head tabs 228 and the card 23 on the drum 89 at the locations 232 and 233 shown in FIG. 12.

The ribbon 248 is dispensed from a cartridge 249 which contains a supply of the ribbon.

A ribbon guide 251 has a guide portion 252 projecting under the ribbon 248 (see FIGS. 11, 12 and 15). As seen in FIG. 12, the guide portion 252 has cutouts 254 to clear the printing tabs 228 and arms 226 at the locations 232 and 233.

The ribbon 248 can be inserted or exchanged when the screw 208 has been loosened whereby the spring 207 swings the assembly 196 outwardly about the pivot 202 (see FIG. 11).

The printing mechanism 189 can be moved laterally on its supporting rod as shown in dotted lines at 291 in FIG. 2, so that different columns can be printed on the record cards.

As seen in FIGS. 3 and 8, the drum 89 has an arm 292 which contacts a stop 293 on the frame structure 44 when the drum 89 has returned to its initial position after completion of the printing operation.

As shown in FIG. 9, a hold down spring 295 may be provided to positively retain the card 23 as it is wrapped around the drum 89.

FIG. 9 also shows a readout head structure 296 which may be provided to read information from the card 23 at or in the vicinity of the drum 89. This would be in keeping with the broad scope of the subject invention, which contemplates printing, reading and/or the performance of another function or functions relative to the cards 23 in the region of the drum 89.

Now that an understanding concerning the illustrated preferred embodiment of the invention has been gained, it may be helpful to summarize the function of the illustrated apparatus in terms of the subject invention.

To this end, it will be recognized that the motor 209 at its output shaft 212 provides pulsed motive power subject to terminal fluctuation as above defined. The coupling 213 with its buffer springs 216 yieldably couples the motive power provided at the shaft 212 to the printing head in order to pulse the printing head into a predetermined position.

The detent 224 cooperate with the notches 222 of the ring 221 on the printing head 214 in order to releasably retain the printing head in any stepped position.

At the end of a stepping cycle, the yieldable coupling 213 will absorb the motive power fluctuations which occur after the last stepping pluse of a stepping cycle.

Details of a preferred embodiment of the invention are illustrated on an enlarged scale in FIG. 16. In particular, the buffer spring 216 is shown therein in the form of a squared off letter G, having a first leg 261 extending via a radial slot 262 into an axial slot 263 in the cup-shaped coupling part 216.

The buffer spring 216 has a bight portion which extends in parallel to the axis of rotation of the motor shaft 212 and printing head 214. The buffer spring 216 further has a leg 265 which extends through a slot 266 in the coupling part 217 and into a bore 267 in the printing head collar which forms the coupling part 218. The lateral dimension or width of the slot 266 is somewhat greater than the thickness of the buffer spring 216. In this manner, the slot 266 in the coupling part 217 permits a limited lateral deflection of the buffer spring relative to the axis of rotation of the printing head 214.

In the preferred embodiment shown in FIGS. 11 and 15, there are two buffer springs 216 at diammetrically opposite sides of the coupling 213. In FIG. 16, only one buffer spring 216 has been shown as a showing of the other buffer spring would be just a mirror-image duplication thereof. Rather than showing such duplication, FIG. 16 illustrates the set screw 219 which fastens the coupling part 217 to the motor shaft 212. FIG. 16 also shows the cup-shaped extension 269 of the coupling part 217 which reaches over the printing head collar which forms the coupling part 218. The previously mentioned slot 266 for each buffer spring is machined or otherwise provided in the cup-shaped extension 269 of the coupling part 217, with the length of the slot 266 extending in parallel to the axis of rotation of the printing head 214 and the width of the slot 266, which limits lateral deflection of the spring 216, extending at right angles to the axis of rotation of the printing head 214.

In this manner, the springs 216 nto not provide their buffering action between the stepping motor output shaft 212 and the printing head 214, but also attach the printing head 214 to the coupling 217 and, via the set screw 219, to the drive shaft 212.

Broadly speaking, it will be noted that the coupling part 217 with set screw 219 connect the end 261 of the spring 216 to the motive power shaft 212, while the collar 218 connects the other end 265 of the spring 216 to the printing head 214.

In accordance with the subject invention, it is important that the coupling 213 be yieldable. In the illustrated preferred embodiment, this is accomplished by the use of flexible or deflectable buffer springs 216. However, the invention is not so limited, since other yieldable devices, such as flexible or elastic cushions, fluid couplings and other yieldable devices can be employed. This will become more readily apparent, as a further function of the coupling device 213, in addition to the above mentioned function, is considered.

In particular, the yieldable coupling device 213 beneficially reduces the initial inertia load on the stepping motor 219. Since the coupling device 213 is yieldable, the motor 209, at the beginning of a stepping cycle will not be instantly located with the full inertia of the printing head. Rather, the yieldable quality of the coupling device 213 gives the stepping motor 209 a brief period in which it may develop power and carry out a small rotary movement with its output shaft 212 before it will encounter the inertia of the printing head 214 and the load provided by the spring biased detent 224 when the slack of the buffer springs 216 has been taken up as they hit the sides of the associated slots 266. This in effect reduces the starting time of the stepping motor, as the stepping motor is not instantly burdened with a heavy load.

It will thus be noted that the subject invention reduces both starting time and stopping time of the printing head and, therefore, overall printing speed. In addition, wear and tear and equipment expense are kept at a minimum.

The subject extensive disclosure will suggest several modifications and variations within the spirit and scope of the invention to those skilled in the art.

Suitable electronic equipment for the portable billing apparatus 28 will now be described with the aid of the last figure of the drawings.

Function and purpose of this electronic equipment are essentially as follows: To enable the photoelectric or magnetic reader 296 to read from each card 23 the information provided thereon by the utility computer 13 and printer 22, to enable the meter reader to input his readings into the portable billing apparatus by means of a keyboard 300, to calculate the new amount due on the basis of the billing information read from the card and the new meter reading supplied through the keyboard 300, to release the ratchet wheel 156 in a controlled manner for a stepped advancement of each card during the printing phase, to actuate the printing head 214 for a printing of the new meter reading and the new amount due on the cards 23 as mentioned above, and to actuate the printing hammers 246 during such printing process.

The heart of the electronic equipment of the portable billing apparatus is a microcomputer 302. Microcomputers have become well-known in recent years as they form the essential part of hand-held or other portable electronic calculating equipment and have found utility in other areas where small computers are of advantage. By way of example, and not by way of limitation, the microcomputer 302 may be adapted from the commercially available MCS-4 Microcomputer. Alternatives are apparent to an integrated circuit designer of average skill from the subject disclosure.

In particular, the microcomputer 302 has a two phase oscillator 304 which clocks a central processing unit (CPU) 305. A data bus 306 leads to and from the central processing unit 305. Random access memories (RAM) 308 and 309 are connected to the central processing unit 305 via data bus 306. Programed read only memories 310 and 311 are connectable to the central processing unit 305 via data bus 306 and an address latch 312. A chip selector 313 enables the address latch 312 to select one out of n programed read only memories which, in actuality, are preferably present in the form of integrated circuit chips, wherein n is the number of programed read only memories.

An input/output interface device 316 selectively connects input ports (IP) 317, 318 and 319 and output ports (OP) 320 and 321 to the central processing unit 305 via data bus 306. For this purpose, the interface device 316 in conjunction with the chip selector 313 provides an input command via a line 323 to the input ports 317 to 319, and an output command via a line 324 to the output ports 320 and 321.

The item 296 is preferably a code reader which, for instance, reads the billing information from the part 32 of the card as provided by the utility computer and printer. The signals produced by the reader 296 are amplified and processed by a signal processor 331 which may be of a basically conventional type.

A line 332 applies the amplified and processed read message to the input port 317 whence it is applied to the central processing unit 305 by the interface device 316 and data bus 306.

The RAM device 309 is preferably of a conventional integrated circuit design having an output port 362 in addition to a read/write memory 364.

The meter reader inputs the reading for the particular customer through the keyboard 300 which has digit keys (1 through 9), a decimal key (0), an entry key (E) and a clear key (C). The keyboard device 300 is preferably or a coordinate or cross-bar type receiving its input via a line 334 and output port 362 of the integrated RAM device 309 and supplying its output via a line 335 to the input port 319.

The data provided by the keyboard device 300 is supplied via the interface device 316 and data bus 306 to the central processing unit 305 where it is processed together with the billing information read by the reader 296. Such processing is effected under the control of the programed read only memories 310 and 311. Accordingly, information which applies to customers in general may be stored in the program of the read only memories thereby saving space on the cards 23 and additional reading steps.

The RAM device 308 is preferably of a conventional integrated circuit design having an output port 361 in addition to a read/write memory 363. As the microcomputer 302 has completed a calculating operation and is ready for the printing process, a driver 341 is energized via a line 342 and the output port 361 of the integrated RAM device 308. The driver 341 may be of a conventional type which alternatively energizes the electromagnets 184 and 185 in order to actuate the pawl into controlling a stepped advance of the ratchet wheel 156 and thereby of the card wrapped on the drum 89.

Information on the data to be printed is supplied via the output port 320 and a line 344 to a driver 345.

The driver 345 may be of a conventional type which energizes the stepping motor 209 with electrical pulses so that the rotary printing head. 214 is actuated to the correct angular position for the printing of each clear text and corresponding code text character.

In order to permit the equipment to orient itself as to the position of the printing head 214, an angular head position sensor 347 is provided. The sensor 347 may be of an electrooptical, electromagnetic or other conventional type to sense the actual angular position of the printing head 214. A line 349 applies the position sensing signal to the input port 318 for consideration by the central processing unit 305 in its control of the printing head.

Whenever the printing head 214 has been actuated to the desired angular printing position, the microcomputer 302 energizes the hammer actuator 246 via the output port 321 and a line 351.

Movement of the printing mechanism for printing in different columns on the card 31, if needed, may be controlled in a similar manner by the microcomputer 302 so that no specific equipment is disclosed for this purpose.

Rather, the figure under discussion discloses electronic equipment which will satisfy the basic data processing and control needs of the portable billing apparatus 28. Refinements for particular billing situations may be added on the basis of conventional circuit design.

I claim:

I. In apparatus for printing characters from a multiposition printing head, the improvement comprising in combination:

means for providing pulsed motive power subject to terminal fluctuation; means advancing said printing head with said pulsed motive power to any printing position, said advancing means include means for yieldably coupling said motive power means to said printing head;

means coupled to said printing head for releasably retaining said printing head in any printing position whereby said yieldable coupling means absorb said motive power terminal fluctuation; and

means including printing hammer means separate from said releasable retaining means for printing characters from said printing head.

2. An apparatus as claimed in claim 1, wherein:

said printing head is a rotary printing head having a plurality of angular printing positions;

said motive power providing means include means for providing pulsed rotary motive power subject to angular terminal fluctuation;

said advancing means include means for yieldably coupling said pulsed rotary motive power means to said rotary printing head to step the printing head to any angular printing position;

said retaining means include means coupled to said rotary printing head for releasably retaining said rotary printing head in any angular printing position whereby the yieldable coupling means absorb said angular terminal fluctuation; and

said printing means include printing hammer means separate from said releasable retaining means for printing characters from said rotary printing head.

3. An apparatus as claimed in claim 2, wherein:

said yieldable coupling means include resilient means for coupling said motive power to said printing head.

4. An apparatus as claimed in claim 2, wherein:

said yieldable coupling means include spring means extending essentially parallel to the axis of rotation of said rotary printing head, means for connecting a first end of said spring means to said motive power providing means, and means for connecting a second end of said spring means to said rotary printing head.

5. An apparatus as claimed in claim 4, wherein:

said yieldable coupling means include means for limiting lateral deflection of said spring means relative to said axis of rotation.

6. An apparatus as claimed in claim 2, wherein:

said releasable retaining means include resilient detent means coupled to said printing head.

7. An apparatus as claimed in claim 1, wherein:

said yieldable coupling means include resilient means for coupling said motive power to said printing head.

8. An apparatus as claimed in claim 1, wherein:

said yieldable coupling means include spring means, means for connecting a first end of said spring means to said motive power providing means, and means for connecting a second end of said spring means to said printing head.

9. An apparatus as claimed in claim 8, wherein:

said yieldable coupling means include means for limiting deflection of said spring means.

1 10. an apparatus as claimed in claim 1, wherein:

said releasable retaining means include resilient detent means coupled to said printing head. 11. In apparatus for printing characters, the improvement including in combination:

a rotary character printing head having a plurality of angular printing positions;

means including a stepping motor having a motor shaft for providing about an axis of rotation pulsed rotary motive power for stepping said printing head, said pulsed rotary motive power being subject to terminal fluctuation;

means for yieldably coupling said printing head to said stepping motor shaft;

means including a spring-biased detent for releasably retaining said rotary printing head in each of said angular printing positions upon deenergiation of said stepping motor means whereby said yieldable coupling means absorb said terminal fluctuation of said rotary motive power; and

means including printing hammer means separate from said printing head retaining means for printing characters from said printing head.

12. An apparatus as claimed in claim 11, wherein:

said rotary printing head includes a plurality of notches corresponding to said angular printing positions; and

said spring-biased detent is coupled to said notches.

13. An apparatus as claimed in claim 11, wherein:

said yieldable coupling means include a buffer spring having a first leg connected to said motor shaft, a bight portion extending essentially parallel to the axis of rotation of said motor shaft, and a second leg connected to said rotary printing head.

14. An apparatus as claimed in claim 13, wherein:

said rotary printing head has a collar having a lateral aperture; and

said second leg of said buffer spring extends into said lateral aperture of said printing head collar.

15. An apparatus as claimed in claim 14, wherein:

said rotary printing head includes an annular element connected to said collar and having a plurality of notches corresponding to said annular printing positions; and

said spring-biased detent is coupled to said notches.

16. An apparatus as claimed in claim 15, wherein:

said yieldable coupling means further include a coupling member connected to said motor shaft and having a slot having a width greater than the thickness of said buffer spring for receiving part of said second leg of said buffer spring.

17. An apparatus as claimed in claim 16, wherein:

said coupling member has an axial slot for receiving said first leg of said buffer spring.

18. An apparatus as claimed in claim 17, wherein:

said coupling member has a radial slot adjacent said axial slot for receiving a further part of said buffer spring. 

1. In apparatus for printing characters from a multi-position printing head, the improvement comprising in combination: means for providing pulsed motive power subject to terminal fluctuation; means advancing said printing head with said pulsed motive power to any printing position, said advancing means include means for yieldably coupling said motive power means to said printing head; means coupled to said printing head for releasably retaining said printing head in any printing position whereby said yieldable coupling means absorb said motive power terminal fluctuation; and means including printing hammer means separate from said releasable retaining means for printing characters from said printing head.
 2. An apparatus as claimed in claim 1, wherein: said printing head is a rotary printing head having a plurality of angular printing positions; said motive power providing means include means for providing pulsed rotary motive power subject to angular terminal fluctuation; said advancing means include means for yieldably coupling said pulsed rotary motive power means to said rotary printing head to step the printing head to any angular printing position; said retaining means include means coupled to said rotary printing head for releasably retaining said rotary printing head in any angular printing position whereby the yieldable coupling means absorb said angular terminal fluctuation; and said printing means include printing hammer means separate from said releasable retaining means for printing characters from said rotary printing head.
 3. An apparatus as claimed in claim 2, wherein: said yieldable coupling means include resilient means for coupling said motive power to said printing head.
 4. An apparatus as claimed in claim 2, wherein: said yieldable coupling means include spring means extending essentially parallel to the axis of rotation of said rotary printing head, means for connecting a first end of said spring means to said motive power providing means, and means for connecting a second end of said spring means to said rotary printing head.
 5. An apparatus as claimed in claim 4, wherein: said yieldable coupling means include means for limiting lateral deflection of said spring means relative to said axis of rotation.
 6. An apparatus as claimed in claim 2, wherein: said releasable retaining means include resilient detent means coupled to said printing head.
 7. An apparatus as claimed in claim 1, wherein: said yieldable coupling means include resilient means for coupling said motive power to said printing head.
 8. An apparatus as claimed in claim 1, wherein: said yieldable coupling means include spring means, means for connecting a first end of said spring means to said motive power providing means, and means for connecting a second end of said spring means to said printing head.
 9. An apparatus as claimed in claim 8, wherein: said yieldable coupling means include means for limiting deflection of said spring means.
 10. An apparatus as claimed in claim 1, wherein: said releasable retaining means include resilient detent means coupled to said printing head.
 11. In apparatus for printing characters, the improvement including in combination: a rotary character printing head having a plurality of angular printing positions; means including a stepping motor having a motor shaft for providing about an axis of rotation pulsed rotary motive power for stepping said printing head, said pulsed rotary motive power being subject to terminal fluctuation; means for yieldably coupling said printing heAd to said stepping motor shaft; means including a spring-biased detent for releasably retaining said rotary printing head in each of said angular printing positions upon deenergiation of said stepping motor means whereby said yieldable coupling means absorb said terminal fluctuation of said rotary motive power; and means including printing hammer means separate from said printing head retaining means for printing characters from said printing head.
 12. An apparatus as claimed in claim 11, wherein: said rotary printing head includes a plurality of notches corresponding to said angular printing positions; and said spring-biased detent is coupled to said notches.
 13. An apparatus as claimed in claim 11, wherein: said yieldable coupling means include a buffer spring having a first leg connected to said motor shaft, a bight portion extending essentially parallel to the axis of rotation of said motor shaft, and a second leg connected to said rotary printing head.
 14. An apparatus as claimed in claim 13, wherein: said rotary printing head has a collar having a lateral aperture; and said second leg of said buffer spring extends into said lateral aperture of said printing head collar.
 15. An apparatus as claimed in claim 14, wherein: said rotary printing head includes an annular element connected to said collar and having a plurality of notches corresponding to said annular printing positions; and said spring-biased detent is coupled to said notches.
 16. An apparatus as claimed in claim 15, wherein: said yieldable coupling means further include a coupling member connected to said motor shaft and having a slot having a width greater than the thickness of said buffer spring for receiving part of said second leg of said buffer spring.
 17. An apparatus as claimed in claim 16, wherein: said coupling member has an axial slot for receiving said first leg of said buffer spring.
 18. An apparatus as claimed in claim 17, wherein: said coupling member has a radial slot adjacent said axial slot for receiving a further part of said buffer spring. 